Cylinder Head Installed
(Intake or exhaust side as applicable)
The intake and exhaust camshafts can be changed in the vehicle
Caution: Incorrect removal/installation without help of fixture could damage or break the camshaft. Valves could also be bent through contact with the piston crowns. Always note installation instructions and use specified special tools, procedures, and sequences.
Removal
Removal of camshaft is described separately from installation. Assembly sequence for removal and installation is different.
Removing VANOS adjustment unit.
Remove the loosened screws from the exhaust sprocket wheel.
Unfasten nuts from intake camshaft.
Version without plate spring
Remove thrust washer (1).
Version with plate spring
(1) Thrust washer approx. 4 mm thick
(2) Plate spring
(3) Thrust washer approx. 2 mm thick
Remove thrust washers and plate spring.
Remove sprockets together with chain.
Unscrew thrust washer bolts.
Remove thrust washer.
Remove sensor gear.
Unscrew secondary chain tensioner.
Unscrew chain guide.
Caution:
^ Strong spring force.
6 Unfasten cylinder for chain tensioning piston.
Lift off sprocket with chain.
Protect timing chain to prevent it from falling.
Caution:
^ To prevent damaging valves when fitting the camshafts, no pistons should be in TDC position.
^ Pull back special tool 11 2 300 (setting mandrel) until the flywheel is no longer located in position.
^ Lift timing chain and hold under tension. Rotate engine counter-enginewise approx. 30, using the central screw.
Unscrew studs.
Prepare special tool 11 3 260.
Fit special tool 11 3 260 to cylinder head and screw into spark plug threads in cylinders 1 and 4.
Tightening Torque, refer to Engine, Specifications
Caution:
^ Bearing cover 1 on intake camshaft is centered on hollow dowels.
^ To prevent the intake camshaft from tilting in the bearing strip, remove bearing cover 1.
Turn the eccentric shaft to pre-tension the bearing caps.
Unfasten nuts on bearing cover.
Remove tension from the eccentric shaft and remove special tool 11 3260.
Remove bearing covers and place to one side in orderly fashion. Remove camshaft.
If necessary, remove complete bearing strip with bucket tappets.
Brace bucket tappets with special tool 11 3 250.
Lift out complete bearing strip with bucket tappet.
Note: Worn bucket tappets may only be reused in the same tappet bore
Check bearing points on bucket tappets for signs of wear (scoring).
The bearing strips are marked with "A" for exhaust side and "E" for intake side.
Note centering dowels on retaining pins at bearing points 2 and 7.
Install bearing strips.
If necessary, replace splined shaft in intake camshaft.
Clamp camshaft with protective vice jaws.
Remove splined shaft.
Installation:
Tightening Torque, refer to Engine, Specifications.
Note: Differentiating features of camshafts on sprocket flanges:
A = Exhaust camshaft
E = Intake camshaft
Installation
Installation of camshaft is described separately from removal.
Assembly sequence for removal and installation is different.
Caution: The bucket tappets expand when not subjected to load by the camshaft and therefore require some time before they can be pushed back down. During a rapid assembly sequence, the "closed" valves may still be open and be in contact with the pistor
You must adhere to the following waiting periods after installing the camshaft and before cranking the engine back to the TDC position.
- Room temperature (20°C) 4 min.
- 1O°C - 20°C 11 min.
- 0°C - 10°C 30 min..
Install camshafts with tips on intake and exhaust valves pointing towards 1st cylinder.
Fit bearing cover.
Note: The bearing covers are clearly marked and can be read from the exhaust end:
A1 - A7 for the exhaust end
E1 - E7 for the intake end
Fit special tool 11 3 260 to cylinder head and screw into spark plug threads of cylinders 1 and 4.
Tightening Torque, refer to Engine, Specifications
Turn the eccentric shaft to pre-tension the bearing caps.
Tighten down bearing cover.
Tightening Torque, refer to Engine, Specification.
Remove special tool 11 3 260.
Caution:
^ Do not damage the cylinder head.
^ Machine open-end wrench accordingly if necessary.
^ Align camshafts with open-end wrench.
Fit special tool 11 3 240 to camshafts on cylinder 6.
Note: Camshaft adjustment is correct if special tool 11 3 240 bears on the cylinder head without gaps.
Lift timing chain and hold under tension.
Rotate engine from the 30° before TDC position engine-wise up to TDC position.
Secure crankshaft in TDC position with special tool 11 2 300.
Caution: Remove special tool 11 2 300 (plug mandrel) before switching on the engine.
Fit primary timing chain to sprocket.
Fit sprocket to exhaust camshaft with threaded bores on left side aligned down the deep bores.
Install special tool 11 4 220 in chain tensioning sleeve.
Screw in the adjusting screw to touch the bow cover, but do not yet tighten it.
Note: Long sprocket slots are now centered on threaded bores.
Install chain guide.
Install secondary chain tensioner.
Fit sensor gear to the intake camshaft.
Caution: There is a danger of mixing up:
1 Studs for cylinder-head covers.
2 Studs for thrust washers and sprockets (version without plate spring).
3 Studs for thrust washers and sprockets (version with plate spring).
Fit thrust washer and tighten down with dowels.
Tightening Torque, refer to Engine, Specifications
Caution:
^ Correctly install sprocket for intake camshaft.
^ Flat side facing VANOS housing, collar facing camshaft.
Mount both sprockets together with chain. Slots centered.
Version with plate spring
Fit approx. 2 mm thickness of thrust washer (3).
Version with plate spring
Note:
^ Note installation direction of plate spring.
^ Install large support diameter facing towards camshaft.
^ Install plate spring (2).
Version with plate spring
Fit approx. 4 mm thickness of thrust washer (1) to the intake camshaft.
Version with plate spring
Install nuts and tighten down.
Tightening Torque, refer to Engine, Specifications.
Version without plate spring
Fit thrust washer (1) to the intake camshaft.
Version without plate spring
Tighten down thrust washer (1) with nuts.
Tightening Torque, refer to Engine, Specifications
Fit shim and screws to the exhaust camshaft.
Fit screws with zero backlash: sprocket remains able to move.
Installing VANOS adjustment unit.
Assemble engine.